Alpha-chlorovinylsilanes



Patented June 20, 1950 a-CHLOROVINYLSILANES Leo H. Sommer, StateCollege, Pa., assignor to Dow Corning Corporation. Midland, Mlch., a

corporation of Michigan No Drawing. Application June 3, 1949,

Serial No. 97,084

Claims. (Cl. 260-4482) 2 The present invention relates to polymerizableit with chlorine gas whereby there is obtained the organosiliconcompounds.

In the organosilicon field most of the known materials contain as theorganic substituents non-functional radicals. Polymers are prepared bythe hydrolysis of functional materials, such as chlorine, linked to thesilicon, whereby the organosilicon polymers are siloxanes. Alkenylderivatives of silicon have been described, and in particular,triethylvinylsilane. Such a material should be an excellent basis forthe preparation of a new polymer variety, i. e. polymers in which thechain structure is a carbon chain and alternate carbon atoms aretrialkylsilyl substituted. While this is an intriguing possibility, Ihave found that in general the alkenyl silanes do not polymerizesatisfactorily. The vinyl silanes are sluggish. This necessitates theuse of catalysts, such as aluminum chloride, in order to effectpolymerization. The products so obtained are not of substantialinterest. Longer chain alkenyl silanes in which the double bond isfurther removed from the silicon polymerize more normally. The productsof such a'polymerization are too branched to be of much interest in highpolymer chemistry.

Objects of the present invention are the provision of silanes whichundergo olefin polymerization readily with the formation of highpolymers, and methods for the production thereof.

silanes in accordance herewith contain the e-ehlorovinyl radical linkedto the silicon atom. Thus, the present silanes are of the type formulaCHz=CClSiRa-1.Xn where R represents a hydrocarbon radical of the groupconsisting of alkyl and monocyclic aryl, and X represents a substituentof the group consisting of halogen and alkoxy and n has an average valuefrom 0 to 3.

These silanes may be prepared in accordance with the method hereof bythe dehydrohalogenation of p-dichloroethyltrihalosilanes. Thisdehydrohalogenation product may then be substituted with organicradicals by reaction thereof with Grignard reagents, with organosodiumor with organolithium compounds.

The a,p-dichloroethylsilanes may be..prepared from an ethylsilane by themonochlorination of the ethyl radical followed by thedehydrohalogenation of the chloroethyl silane to a vinyl silane. Thismethod is described by Ushakov at Journal of General Chemistry (USSR),volume 7, pages 2492-2498. The vinyltrichlorosilane may then bechlorinated, as shown in my copendingapplip-dichloroethyltrichlorosilane.

The ,p-dichloroethyl derivative so obtained may be dehydrochlorinated bywell known dehydrochlorination methods, as for example. by reacting itwith tertiary amines, particularly the cyclic tertiary amines such asquinoline, picoline or the like.

The a-chlorovinylsilanes so prepared may be employed for a wide varietyof uses. They may be employed for coating glass. They may becopolymerized with organic olefins, such as styrene. vinyl chloride orvinyl acetate and the copolymer containing hydrolyzable chloride beemployed for laminating sheet glass or for impregnating glass fiberfabric, whereby to obtain good plastic to glass bonding. Theu-chlorovinylchlorosilanes, modified by substitution of organic radicalsfor some of the chlorine atoms on the silicon, may likewise be employed.Those which contain no silicon bonded chlorine may be ccpoiymerized withorganic vinyl polymers, such as those indicated, whereby to obtainsubstantial modification of the physical properties thereof.

Also the a-chlorovinylsilanes which contain functional chlorine may becohydrolyzed and cocondensed with other functional organosilanes wherebyto obtain siloxane copolymers which may be thermoset by heating.

Example 1 A mixture of 50.5 parts by weight of cap-d1-chloroethyltrichlorosilane and 32 parts of quinoline was heated.Vigorous foaming took place 35 when the flask temperature reached C. The

product was distilled, whereby there was obtained the desired material,e-chlorovinyltrichlorosilane, boiling at C. at 750.3 mm.

Example 2 0.4 gram moles of a-chlorovinyltrichlorosilane in 56 ml. ofanhydrous ether was added to 1.32 gram moles of methyl magnesium bromidein 530 m1. of ether. The reaction mixture was main- 5 tained at 0 C.with stirring until the reaction cation filed simultaneously herewith,by reacting a was complete, as noted by the absence of furtherprecipitation. Excess Grignard reagent was hydrolyzed by pouring overcracked ice and the product was made slightly acid. The product was thendehydrated, stripped to remove the ether and iractionaliy distilled. Theproduct a-chlorovinyltrimethylsilane had the following properties:

den-0.8875

a -1.4299 B. P. C.--105/729 mm.

Example 3 0.4 gram moles oi phenyl magnesium bromide in 30 ml. ofanhydrous ether was added to 0.4 gram moles ofa-chlorovinyltrichlorosilane in 55 m1. of anhydrous ether. The reactionmixture 6 was maintained at about 0 C. with stirring. The reactionproduct, following substantial completion of the reaction, was filtered,the ether stripped and the residue tractionally distilled under vacuum.The product, m-chlorovinylphenyldichlorosilane had a B. P. in the rangebetween 79 and 92 C. at 2 mm.

That which is claimed is:

1. CHz=CClSiRa-Xn where R represents a hydrocarbon radical of the groupconsisting of alkyl and monocxclie aryl,-x represents a substituent orthe group consisting or halogen and alkoxy and n has an average valuefrom 0 to 3.

2. .CH:=CClBiCh.

3. CH:=CClSi(CHa)a.

4. CHa=CCl8iCaHsCh 5. The method of producing a-Chlol'OVil'iYlsilaneswhich comprises dehydrohalogenating a material of the type CHzClCHClBlX:whereby a product is obtained of the type CH2=CC1S1X2 where X representsa halogen.

LEO H. SOMMER.

REFERENCES CITED The following references are of record in th file ofthis patent:

Kurd, "Jour. Am. Chem. 800.," vol. 67 (1945), pages 1813, 1814.

1. CH2==CCISIR3-NXN WHERE R REPRESENTS A HYDROCARBON RADICAL OF THEGROUP CONSISTING OF ALKYL AND MONOCYCLIC ARYL, X REPRESENTS ASUBSTITUENT OF THE GROUP CONSISTING OF HALOGEN AND ALKOXY AND N HAS ANAVERAGE VALUE FROM 0 TO 3.